According to Matthew and Mark, the apostles joined in singing a hymn before leaving the upper room after the Passover meal. Scholars agree that the "hymn" would include at least a portion of the Hallel, Psalms 113 to 118, traditionally associated with the Passover celebration.
At this point John sets down the Master's inspired discourse on spiritual unity (15:1 to 16:33). In the vine, its branches, and its fruit he found a practical illustration of the essential unity with God that he so consistently exemplified. Some have thought this allegory prompted by the sight of the vineyards along the way that led out of the city toward the Mount of Olives.
In the opening portion of his discourse (see 15:1-11) Jesus unfolds the glorious potential in that spiritual union between himself and his disciples, under the Father's care. "I am the true vine, and my Father is the husbandman....I am the vine, ye are the branches: He that abideth in me, and I in him, the same bringeth forth much fruit." He speaks of "the true vine" here as he has spoken of "the true bread from heaven" (6:32) and as John speaks earlier of "the true Light" (1:9)—the spiritually perfect, the genuine and ideal.
